Left Ventricular End Diastolic Dimension, [ Designated as safety issue: No ]

QT interval and [ Designated as safety issue: No ]

T wave amplitude [ Designated as safety issue: No ]

Estimated Enrollment:

172

Study Start Date:

October 2003

Study Completion Date:

December 2005

Detailed Description:

The combination of congestive heart failure and atrial fibrillation is a common co morbidity, although the exact prevalence of AF in the heart failure population is still unclear. Recent studies show a prevalence of AF ranging from about 10% to 50%, although the type of AF observed and investigated in these studies is not always clearly described.

A number of mechanisms attributed to congestive heart failure may contribute to the development of AF Experimental congestive heart failure promotes sustained AF by ionic remodeling and increased interstitial fibrosis. In contrast to tachycardia-mediated AF, in congestive heart failure no shortening of atrial refractoriness occurs. Atrial tissue stress caused by congestive heart failure may also contribute to promotion of AF by inducing triggered activity, affecting atrial refractoriness properties or resulting in increased tissue mass supporting re-entry [31]. Existence of these mechanisms suggests that treatment of congestive heart failure may also influence the development and progression of AF in these patients. Conversion of chronic AF has been observed in patients with congestive heart failure treated with biventricular pacing Ventricular ionic remodeling likely underlies the increased risk for proarrhythmia in heart failure patients exposed to antiarrhythmic drugs, prolonging the action potential duration , which therefore should be avoided in patients with congestive heart failure.

The independent prognostic significance of AF in heart failure patients is still not completely clear. Results from some recent studies suggest no independent prognostic significance of AF in heart failure patients Result from other large studies on congestive heart failure suggest an independent prognostic effect of AF in patients with AF and congestive heart failure, associated with an increased risk for pump failure death and all-cause mortality a significantly reduced 1-year survival and a higher mortality among heart failure patients who developed AF A recent review with regard to the mortality in studies on congestive heart failure suggests that concomitant AF does not have an additional effect on the mortality in patients with severe heart failure, but does increase the mortality in the setting of mild-to-moderate heart failure This observation may be attributed to the fact that the atrial contribution to left ventricular filling is limited in patients with severe diastolic dysfunction, whereas the atrial contribution may still be of hemodynamic importance in mild-to-moderate heart failure

Eligibility

Ages Eligible for Study:

18 Years and older (Adult, Senior)

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

Patient is willing and able to comply with the protocol

Patient is willing to sign written informed consent

Patient is expected to remain available for Follow-up visits

Patient age is 18 years and older

patient is on a stable medication regimen (including beta blockers) for at least 4 weeks prior to enrollment

Baseline criteria: patients should meet all of the following criteria, to be determined at the baseline assessment procedure within 4 weeks prior to device implantation: - New York Heart Association functional classification III or IV

Patients with unstable angina or who have experienced an acute myocardial infarction or received coronary artery revascularization (CABG) or coronary angioplasty (PTCA) within 3 months prior to enrollment or who are candidates for CABG or PTCA

Patients who have experienced CVA or TIA with permanent disability within 3 months prior to enrollment

Post heart transplant patients and patients on an urgency list for cardiac transplantation

Supine systolic blood pressure greater than 170 mm

Patient who are not expected to survive for 8 months of study participation due to other medical conditions

Women who are pregnant or with child bearing potential and who are not on a reliable form of birth control

Serum creatinine greater than 250 mol/l

Untreated hyperthyroidism

Patients enrolled in any concurrent (drug and/or device) study

Patients with an existing implantable cardioverter defibrillator (ICD) or indications for an ICD including those patients with sustained VT within the previous month

Patients with permanent atrial arrhythmias. Permanent atrial arrhythmia is defined as an arrhythmia for which any possible type of cardioversion is not considered or that is recurrent within 24 hours from an attempted cardioversion

Patients with contraindications for implantation of a cardiac pacing device

Patients who are already implanted with a cardiac pacing device for purposes other than Cardiac Resynchronization Therapy

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00156728

Netherlands: The Central Committee on Research Involving Human Subjects (CCMO)France: National Consultative Ethics Committee for Health and Life SciencesUnited Kingdom: Research Ethics CommitteeSerbia and Montenegro: Agency for Drugs and Medicinal Devices